An invalid subnet route refers to that the next-hop failure of the subnet route is invalid. Such condition of invalid subnet route usually appears when the subnet route exists but the next-hop host route of the subnet has been deleted. Specifically, it may appear when an Address Resolution Protocol (ARP) table item of the next-hop host route has been aged but the subnet route which is dynamically generated has not yet been deleted or when the subnet route is statically configured but the ARP table item of the next-hop host route is deleted or aged.
A commonly used method for managing an invalid subnet route in an existing technology is usually to make that the next-hop egress of the subnet route is directed to a Central Processing Unit (CPU), so that a subsequent data message can be sent to the CPU, and then the CPU triggers ARP relearning. However, when there are multiple subnet routes, these subnet routes are simultaneously directed to the same next-hop host route, and when the host route is invalid, the egresses of all the subnet routes may be modified into CPUs, which may cause multiple modification operations of the subnet routes in hardware. When the next-hop host route is restored, all the subnet routes are restored into the egresses to which the host route is directed, and then multiple restoration operations are required. Therefore, the route management may become relatively complicated, and efficiency of switching between invalidity and validity of the next hop is relatively low.